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View Full Version : Shops to balance driveshaft



j03_tj
October 7th, 2013, 12:10 PM
Anyone know of any other local shops that can balance my driveshaft? Bayshore told me there machine only goes up to 500 RPM, and I don't like going to Reno Driveline and Gear. Anyone else know of a local shop that can spin and balance a shaft faster than 500 RPM?

xkmacx86
October 7th, 2013, 02:52 PM
Isnt there a driveline shop across the street from the triple s tire shop

Special K
October 7th, 2013, 06:40 PM
500 rpm is all thats needed to get an accurate balance, worked in the drivetrain business for 10 years around all different balancers, very few actually high speed balance, and I've found bayshore's machine to be very accurate

j03_tj
October 7th, 2013, 07:39 PM
500 rpm is all thats needed to get an accurate balance, worked in the drivetrain business for 10 years around all different balancers, very few actually high speed balance, and I've found bayshore's machine to be very accurate

Hey Kenny, thanks for chiming in. Hope you're doing good in your new adventures. Don't know if you remember me, green TJ-Brad, You guys built it, sometime in the spring (when you were there). I highly doubt it's not balanced, but trying to eliminate any variable in my vibration hunt. To tell you the truth, it vibrated before the new shaft, but was fine for years, hell, I'm even about 1/2" lower now, and I've adjusted my pinion angle till I'm blue in the face, and it won't go away.

Just reading around the internet (good old trusty internet you know,lol) made me find lots of thread and articles about faster balancing speed, even saw an article about factory balancing being 3500 rpm. Also saw where Denny's driveshaft offers up to 10,000 rpm. I could imagine the manufacturer of the Bayshore machine determined the 500 rpm range was sufficient. I've read that steep operating angles have a pretty good effect on the balance of a shaft, my TJ has a fairly steep angle, so maybe I fall into a category where high rpm balance might be needed. I'm all for not doing it or needing it, but from what I read it made is sound like it is common place with lifted jeeps and high output vehicles.
All the forums talk about 7000 rpm balance being reasonable for a high output vehicle. mine is not that of course. But my vibe happens at 35mph and figure my driveshaft is going around 1600 rpm. I only go off of what is out there on the internet, so let me know why it might just be hype? Also, for all know there are threads out there that debunk it, I just don't know.

Also for the record, Bayshore has been great to me.

If anyone else has any info on drive shaft balance speed I'm interested.

j03_tj
October 7th, 2013, 07:43 PM
Isnt there a driveline shop across the street from the triple s tire shop

In case I do it, Is that the Triple S on Glendale?

owenst7
October 7th, 2013, 08:20 PM
Remove driveshaft, go for a drive without it. Variables eliminated.

CashMoney
October 7th, 2013, 09:00 PM
Remove driveshaft, go for a drive without it. Variables eliminated.

I agree. I almost wonder if you have a tire out of round or bent axle shaft

Reno Computer Repair
October 7th, 2013, 09:01 PM
You could also mount a go pro underneath and take a spin. I know a guy who did that.....A>S>

j03_tj
October 7th, 2013, 09:21 PM
I've pulled the rear drive shaft and the vibe went away. Pulled the front and the vibe stayed.
I put my OEM axle shafts back in and the vibe stayed. I put new bearings on my alloy shafts and stuck them back in and vibe still shows. I downloaded an ap for my phone and recorded the frequency of the vibe and it is at 26hz, same as the driveshaft going 35mph. Preformed the same measurement at 30mph and again at 40 and the measured frequency changed to correspond with the drive shaft speed. Like I said the problem showed up when I put a little shorter springs on when I was still on my older driveshaft, so I don't really think its the driveshaft. I have two sets of tires that I know the new winter set road fine. I even had those balanced twice and again road force balanced just for kicks, of corse also tried rotating them. I'm leaning towards changing my transmission bushings. The vibe is not really noticeable except by looking at or holding the steering wheel. Had my buddy in the passenger seat and he said he couldn't feel it in the seat, but then I showed him the steering wheel and he saw it and put his hand on the wheel and then said oh yeah. It's not bad, just always there between 30-40 mph. I've had my pinion below the driveline by 3 degrees up to 1 below to parallel to over by a couple degrees during lots of one turn adjustments of my control arms. Anyway, not really my intent of this posting, now I just am kind of curious as to what the requires balance speed could/should be with a double cardan shaft operated at angle, but within specs. Oh yeah, I've changed every bushing in all my arms and bars. Sorry for the long text. Thanks for the suggestions.

j03_tj
October 7th, 2013, 09:31 PM
You could also mount a go pro underneath and take a spin. I know a guy who did that.....A>S>

Thanks for the suggestion, I thought about that for sure, but don't have one of those, and don't think I'd get much use out of owning one, except for things like this. I keep trying to talk myself into putting the Jeep on jackstands and driving it at speed, first with the tires off, probably because thats safer for everyone around me, lol. Just kind of sketchy image,especially with the tires spinning and my wife behind the wheel with me crawling around near the underside. Trying to avoid doing it to tell you the truth.

owenst7
October 7th, 2013, 10:53 PM
Thanks for the suggestion, I thought about that for sure, but don't have one of those, and don't think I'd get much use out of owning one, except for things like this. I keep trying to talk myself into putting the Jeep on jackstands and driving it at speed, first with the tires off, probably because thats safer for everyone around me, lol. Just kind of sketchy image,especially with the tires spinning and my wife behind the wheel with me crawling around near the underside. Trying to avoid doing it to tell you the truth.

Check the driveshaft for radial runout. That's more likely to cause vibrations than center of mass, is more likely to have changed under use, and is easier to measure.

j03_tj
October 8th, 2013, 04:50 AM
Check the driveshaft for radial runout. That's more likely to cause vibrations than center of mass, is more likely to have changed under use, and is easier to measure.

You know I did that on the front shaft way back before I started removing shafts, guess ill have to see what the rear one looks like. This rear shaft is only like 3 months old, can't imagine it would be bad? Ill take a look though. Also the shaft is pretty short, only abut 16", so guessing that helps to reduce runout being that there is not much lenght to work with?

So you think since when I pulled the rear shaft and the vibe went away that it means the shaft is bad. I've pulled and pried on the pinion yoke and transfer case output and both are solid. I keep wondering if its something in my transfer case or transmission, but don't know.

Can I also ask what are your thoughts on Bayshore's machine only balancing in the 500rpm range and it being all over the internet to look for at least a 3500+rpm balance??

Fernley818
October 8th, 2013, 07:04 AM
I am no professional by any means. But I do not think your driveline is causing your vibrations. I work with industrial hydraulics, and the machine I build runs what is basically a giant drive shaft and speeds of up to 3000rpm with a cutting head up to 400lbs on one end. Even cutting a half inch of steel it is quiet as can be. The same concept we use to build that I did with my rear driveline. No balance just straightened and indicated within .002" and it has no vibs. Even with the crazy angle and short length. Just my $.02. I hope you find your vibration. I'm very interested to see what the cause is.

owenst7
October 8th, 2013, 10:35 AM
You know I did that on the front shaft way back before I started removing shafts, guess ill have to see what the rear one looks like. This rear shaft is only like 3 months old, can't imagine it would be bad? Ill take a look though. Also the shaft is pretty short, only abut 16", so guessing that helps to reduce runout being that there is not much lenght to work with?

So you think since when I pulled the rear shaft and the vibe went away that it means the shaft is bad. I've pulled and pried on the pinion yoke and transfer case output and both are solid. I keep wondering if its something in my transfer case or transmission, but don't know.

Can I also ask what are your thoughts on Bayshore's machine only balancing in the 500rpm range and it being all over the internet to look for at least a 3500+rpm balance??

Not necessarily. I think something related to that assembly is causing the problem. Could be anything between the back half of the transfer case and the carrier.

I think 500 rpm is probably fine provided that the machine is sensitive enough , which it probably is. Most driveshaft balancing is just to remedy radial run out. the actual center of mass of the shaft is someone arbitrary due to the design and shape of the shaft. my rear shaft is about 44 inches long and I built it on my beer pong table. never balanced, but I built it with very little radial run out and it didn't vibrate until I bent it on rocks.

A lot of late model balancers spin at low speed. I don't know enough about them to tell you why, but if I had to guess, the high rpm systems are probably dated technology that uses buzz words and misunderstanding as marketing. As an engineer, I can tell you that you can measure center of mass without spinning the shaft that fast. But again, I don't know enough about those machines to tell you if they operate the way I'm thinking or not.

By the way, Special K up until recently managed Bayshore, so I'd say his word has more weight here than anyone else's. I'd also say they are the most competent and honest shop in town. They were always extremely generous with me, even though they were frequently swamped And probably didn't have time for the little shit I was bugging them for.

j03_tj
October 8th, 2013, 12:20 PM
Not necessarily. I think something related to that assembly is causing the problem. Could be anything between the back half of the transfer case and the carrier.

I think 500 rpm is probably fine provided that the machine is sensitive enough , which it probably is. Most driveshaft balancing is just to remedy radial run out. the actual center of mass of the shaft is someone arbitrary due to the design and shape of the shaft. my rear shaft is about 44 inches long and I built it on my beer pong table. never balanced, but I built it with very little radial run out and it didn't vibrate until I bent it on rocks.

A lot of late model balancers spin at low speed. I don't know enough about them to tell you why, but if I had to guess, the high rpm systems are probably dated technology that uses buzz words and misunderstanding as marketing. As an engineer, I can tell you that you can measure center of mass without spinning the shaft that fast. But again, I don't know enough about those machines to tell you if they operate the way I'm thinking or not.

By the way, Special K up until recently managed Bayshore, so I'd say his word has more weight here than anyone else's. I'd also say they are the most competent and honest shop in town. They were always extremely generous with me, even though they were frequently swamped And probably didn't have time for the little shit I was bugging them for.

Cool, thanks for your input. Not sure if you remember me, we tried to mount a tire I had on a Jeep Moab rim one day in your driveway, I ended up giving wallyworld $10 and they mounted it. I'm a mech eng too, so I understand stuff, but just so darn much talk out there about faster rpm on balancing. Even saw one manufacturer of a 500rpm machine suggesting higher rpm might be needed due to operating angles, which lifted jeeps have. Yep, near as I can tell its somewhere between the transmission and the rig and pinion, lol. One thing that I still question is that when I pulled the rear shaft and drove on the front shaft the vibe went away. Part of me thinks the problem might still be in the front and it was just suppressed because all the load the front axle was under as it was no longer just rolling, that and the fact that it only shows itself in the steering wheel. Although I can feel it in the seat a little since I'm hypersensitive to it. Anyway thanks for chiming in.

Special K
October 8th, 2013, 06:07 PM
I can prolly pull some strings and have them rebalance it for you (if you pull the shaft)..........I don't want to make promises that aren't mine to keep though, so let me talk to Aaron (branch manager)...............fyi, Aaron is one of the best vibration diagnostic guys around, you might get him to hop in the jeep and go for a ride with you, he's solved many many driveline issues, he's who hired me long ago.

your not the first tj with this issue, and won't be the last, I've battled it for years trying to help customers, and then some guys get lucky and never have an issue, it's truly case by case

j03_tj
October 8th, 2013, 08:49 PM
I can prolly pull some strings and have them rebalance it for you (if you pull the shaft)..........I don't want to make promises that aren't mine to keep though, so let me talk to Aaron (branch manager)...............fyi, Aaron is one of the best vibration diagnostic guys around, you might get him to hop in the jeep and go for a ride with you, he's solved many many driveline issues, he's who hired me long ago.

your not the first tj with this issue, and won't be the last, I've battled it for years trying to help customers, and then some guys get lucky and never have an issue, it's truly case by case

Well I'll say thanks for just offering to see if you can. I would definitely be up for pulling the shaft. One thing that I can think of is I brought the shaft back to have a centering ball dust boot put on, also been wondering when they did that if the parts went back together the same way it had been balanced. I don't know if that little change would affect anything, guessing they probably are used to putting shafts back together the same way they come apart. Who knows, but hey thanks for help and info and whatever you can do. Send me a pm if you want and I can call Bayshore to see what can be done. I think I might have met Arron one afternoon there when I picked up some parts.
Thanks,
Brad

McNasty
December 3rd, 2013, 01:04 PM
Did you ever get this figured out?

j03_tj
December 4th, 2013, 08:55 PM
Did you ever get this figured out?

Nope, still same state. Bayshore was nice and double checked the shaft and said it checked out fine on their balancer. I couldn't leave well enough alone and had to go ahead and take it to RDS to see what a faster balance would say. Like every time I've been there strange things happen. I dropped the shaft off and called them the next day and they said it was ready. When I went to pick it up the guy I was dealing with at the counter said it checked out as fine and that there was no charge. Nice of them and kind of anti-climatic. When I picked the shaft up off the counter I noticed grind marks where the washer/weight used to be and the washer was now welded on about 90 degrees from where it used to be. I pointed it out to the counter guy and he then said, oh yeah we did have to move the weight. Just makes me question why they moved the weight and didn't charge me. Might be nothing, and just nice of them or my conspiracy theory brain can come up with all kinds of weird scenarios. I did out the new transmission bushings in with no change, along with messing with the rear pinion some more even though I know it's not the pinion angle as done test drives with every angle setting there is. I did put the rear end up on jack stands and took it up to 40 mph, but could not get the vibe to occur. Thinking about doing the same with the front end, but it's too cold out now. Had my boss in the jeep yesterday and he confirmed he couldn't feel the vibe in the seat at all, but could definately see it in the steering wheel. I replaced both front axle u joints during the summer hoping that would fix it, but no dice. I've also played around with my front caster to where I highly doubt that's it. My front brake pads are just about worn out and the pads have worn little time grooves in the cast rails they rest on. I've seen posts about guys having to fill weld the grooves and file flat, but my grooves are no where near as bad as some of the pics I've seen. But wondering since the vibe only shows in the steering wheel that it is in the front end and maybe worn pads/rotors and these grooves could have something to do with it. But then again it just doesn't seem likely, but I have heard of worn brake parts causing vibes or shimmys. Well how's that for another long story.